Pop-up drain assemblies for lavatory basins in the prior art have commonly utilized a drain conduit means in the form of a cylindrical tube having an extensive threaded portion at its upper end for receiving a washer and gasket and a flange, for fixing the drain conduit means in the installed condition on the lavatory basin. Said prior art assemblies further commonly utilize a horizontal rod and rod bearing member and bearing seat and retaining means including a removable inner seat member for the rod bearing member, a compression nut and outer seat for the rod bearing member, and an inner seat member and compression nut receiving means that is integral with the cylindrical tube and projects laterally outward therefrom. The prior art removable inner seat member is commonly an insert ring having a short cylindrical exterior surface that is matingly received by a cylindrical counterbore in the inner seat member and compression nut receiving means and having an outwardly facing bearing surface shaped to cooperate with the rod bearing member.
The market for the relevant pop-up drain assemblies is highly competitive with the result that cost reductions are important. It is accordingly the objective of this invention to provide improved pop-up drain assemblies which are functionally sound and durable and which can be marketed and installed more economically than those of the prior art.